FLORIDA KEYS -- Upper Keys fishing guide Chuck Kitto spent his early days on the water without protecting himself from the South Florida sun.

Now after 27 years, he visits a dermatologist twice a year to make sure he doesn't need to cut any more damaged skin from his leg. Kitto says he learned his lesson about skin cancer the hard way, and now he won't take his boat out unless he is covered up. The only part of his body exposed to the sun is his hands.

Kitto, so far, has been lucky not to fall victim to the worst form of skin cancer.

Last week, acting U.S. Surgeon General Boris D. Lushniak issued a public warning about skin cancer, describing it as a major health problem requiring immediate action. According to the American Cancer Society, nearly 5 million people are treated for skin cancer each year, with more cases now being diagnosed annually than lung, breast, prostate and colon cancer combined.

"While many other cancers, such as lung cancer, are decreasing, rates of melanoma -- the deadliest form of skin cancer -- are increasing," U.S. Assistant Secretary for Health Howard K. Koh concurred in the surgeon general's report. "As a skin oncologist who worked in this field for many years, I have cared for both the young and old with skin cancers. Almost all of these cancers were caused by unnecessary ultraviolet radiation exposure, usually from excessive time in the sun or from the use of indoor tanning devices."

"I beg with him to take care of himself," she said, but he refuses to apply sunscreen.

But it's not just captains and others who make their living in the sun who are at risk, Mendoza says. Simply being a Florida Keys resident is enough for exposure to potentially harmful rays.

"It's the incidental rays," she said.

Mendoza says people are vulnerable even when walking back and forth to the car or during any type of brief transit where the skin is exposed to the sun. Whenever going outside, residents should take extra precautions, she said.

Mendoza recommends wearing sunglasses with UV protection, wearing dark-colored clothing and applying at least a 30 spf sunblock every 80 minutes. If the body gets wet, sunblock should be reapplied immediately, she said.

"These are simple steps people can take to protect their body," she said.

Key West oncologist Anesa Ahamad, who works regularly with skin cancer and precancer victims, says people just don't realize how deadly the sun can be.

Melanoma, which accounts for only 2 percent of skin cancer cases, is responsible for most of the 9,000 skin cancer deaths each year in the United States, according to the American Cancer Society. Melanoma rates increased more than 200 percent between 1973 and 2011, according to the Department of Health and Human Services.

In 2012, Michele White, a banker in Key West, noticed what appeared to be acne on her upper lip. After it failed to go away, she had it checked and discovered it was an aggressive form of skin cancer. White was able to make a full recovery with the help of chemotherapy treatment.

Oddly, the threat of death doesn't always provide enough motivation for patients to protect themselves, so Ahamad appeals to their self-image.

"This may sound a little trivial, but any cancer can cause disfigurement," Ahamad said. "Imagine getting it on your nose."

The doctor stressed that people need to cover up and apply sunscreen to make sure they limit future problems.

"People should avoid the pain, suffering and expense, and in some cases, life-threatening situations," the doctor said.

Teens and young adults who don't take the rays seriously could pay the price later in life, Ahamad said.

"My average patient is about 40 or 50, and in many cases, it comes from years of unprotected exposure," she said.

Mendoza and Ahamad also encourage patients to conduct occasional self-checks on their bodies. Any skin that looks abnormal should be brought to the attention of a doctor.